“We told them coming in it was an open competition,” Joe Girardi said after the trio combined for six scoreless frames in yesterday’s Grapefruit League-opening walk-off 6-3 win over the Pirates on Colin Curtis’ three-run home run at George M. Steinbrenner Field. “Their nature is competitive so they are going to go out and do the best they can. They want to be on the team, they want to be the fifth starter. I don’t think I need to remind them.”

So one game in, nobody gained an advantage. Hughes and Chamberlain get a chance to match the trio tomorrow against the Rays.

Girardi said he didn’t want the hurlers competing during bullpen and batting-practice sessions. And he isn’t looking to make a decision off yesterday and tomorrow.

The left field/center field derby was also under way. Brett Gardner started in left and Curtis Granderson was in center, hitting second against Bucs left-hander Paul Maholm.

Each went 0-for-2 and Gardner made a sprawling catch on the track after a strong wind took ex-Met Lasting Milledge’s fly toward center field.

“I have told them I will play where they want me to play,” said Gardner, who according to Girardi will get time in center. “It’s all about getting ready for the season and getting ready for No. 28 [World Series title].”

Until Gaudin is tapped on the shoulder and shipped to the pen — and that is the way to wager — he is believing what he was informed of at the start of camp.

“They told me it was open,” said Gaudin, who started and allowed a hit and fanned one in two innings. “There are five guys for the spot. You have to compete, do the job and go from there.”

Gaudin and Aceves likely are guaranteed a spot in the bullpen, where Chamberlain or Hughes will join them. That leaves Mitre, who logged two perfect innings and struck out one, on the outside.

Aceves followed with two perfect frames, also fanning one.

“I try not to just focus on winning the fifth spot,” Gaudin said. “I have to make sure I get ready for the season. The competition is there but I am not focusing on it. I am focusing on quick outs.

“Whatever the decision is, it won’t be because I put too much pressure on myself. I have to go out and pitch and let the big guys make the decision.”

Gaudin turns 28 in about three weeks and is with his sixth big league team. That has helped Gaudin avoid paying attention to situations beyond his control.

“At a young age I was put through a lot of different movements,” Gaudin said. “I let it get to me. It affected the way I pitched.”

Girardi refuses to say the No. 5 fight is a two-horse race.

“There has been so much talk about Hughes and Chamberlain, the other guys have gone under the radar,” Girardi said. “We are going to do what’s best for the club. You can envision a lot of different scenarios. Let it play out.”